import { OperatorFunction } from 'rxjs';
/**
 * Returns an Observable that emits the value returned by the selector before subscribing to the source Observable.
 *
 * This is similar to startWith(), except with a different value for each subscriber. Use it to create
 * SubjectBehavior/publishBehavior-like semantics without introducing a shared Observable so that subscriptions are
 * still passed down to the source Observable.
 */
export declare function deferBehavior<T, U = T>(valueSelector: () => T): OperatorFunction<U, T | U>;